Industrialization creates habitat features that seem maladaptive for humans: pollution, starvation in some countries, climate change, stress from unnatural work and schooling, plus mating practices and social organization quite different from those in the Pleistocene epoch. Do you think that the low fertility in advanced countries, especially Japan, is due to the maladaptive environment provided by modern life? Usually, fitness and adaptation are related.

I once read an article in Indonesian news website: that young Japanese lack of interest on sexual intercourse. I think theyre not low on fertility. Thats the reason why they score so little on citizen growth, perhaps.

I also think that the environment affect mind rather than only physical. It build new mindset on people head that everythings price will be skyrocketing so you have to save in a lot of way. And one way is to reduce the number of your chilren. Cos raising a kid take a lot of cost. But still you can find here in Indonesia, a familiy with 6 kid or even more.

I stand with the idea that humans are very maladapted to the environment they have made and essentially forced themselves to live in.

- most humans are stressed very easily and often on a daily basis, causing many physiological changes (hormone balances, metabolism ect) that would normally be associated with unease in both captive animals and nervous pets.

- the modern lifestyle is very different to what our ancestors would have dealt with every day. We spend most of our time out of the home either block-learning sometimes pointless things at school or at work earning money to keep our houses. There is very little time for relaxation, group bonding (something else that rarely happens any more, with people keeping to themselves more and more) or contemplation.

- pollution is a cause of infertility all to itself, especially if in copious amounts. Not only this but I believe that living in a society that has a lot of pollution can reflect on the attitude of the person, as all of those toxins and horrible gasses are being breathed in and possibly entering your bloodstream every day.

The human race has reached a point where it is far to intelligent and inquisative to be able to live a life of mundane hunting or gathering, and yet we are barely able to cope with the world we have made for ourselves. I strongly agree that we are poorly adapted to our society, and I do not believe we will adapt to it any better over the coming years.

Both yes and no. In many ways, humans have adapted to industrial society by organizing it along paleolithic lines. In paleolithic times, we only had to deal with maybe a hundred people at a time (our tribe), and thats all that present day humans can deal with, so we organize our political systems to be run by a tribe of elected officials in democratic countries, or a bunch of people appointed by the ruling tribe in others. Our DNA has adapted to the first step towards the industrial society, namely the agricultural society. Societies dependent on dairy products have a low incidence of lactose intolerance, (but still suffer from higher rates of heart disease). Societies dependent on wheat have a lower incidence of gluten intolerance. Societies dependent on alcoholic beverages as a way of purifying their water have a lower incidence of alcohol intolerance. Any society which has gone through the increased population density of cities produced by agricultural surplus has a higher resistance to the diseases produced by this increased population density. 80 percent of the people who come from regions where the plague was prevalent (e.g. europe) have genetic resistance to the plague. Native americans had no resistance to smallpox, etc. and no experience with alcohol. Europeans moving in brought these to America, and they wiped out more native americans than any violence ever did.

Look at the prevalence of near-sightedness. This would not be adaptive in a hunter/gatherer society but before the invention of eyglasses, it was adaptive, because of the division of labor necessary in an industrial society. Near sighted people are adapted to fine work, far-sighted hunter/gatherers are not so much.

I don't think we will ever allow the society to become so out of line with our DNA that it is totally dysfunctional. On the other hand, evolution is still proceeding, and I think that we will always be under pressure to adapt to the new conditions, and this will always result in a certain level of stress. But our paleolithic ancestors were not living in paradise. They had to adapt to a changing world too. The next tribe over the hill discovered how to use flint to make spears, they had to learn and adapt to that too, and that is stressful. Those spears wiped out the woolly mammoth, and so they had to learn new ways to feed themselves. It never ends.

Humans are beautifully adapted to a wide range of environments. Humans are not specialists in the biological sense, but generalists, and can change their way of life to many different environments. Humans live in Arctic frigidity, desert aridity, and tropical heat. Our adaptability comes from highly adaptable technology and culture. This permits us to live extremely well in cities as well as elsewhere.

The reason for low fertility in Japan and elsewhere is choice. When contraception is readily available, people have as many or as few children as they wish. Japanese have fewer children because they choose to have fewer children.

I think its more instinctive than a conscious choice. Sexually reproductive organisms under environmental stress are evolutionarily programmed to reproduce more rapidly and prolifically, in order to evolve their way out of the problem more quickly. Also, they will reproduce more rapidly if the environment can support many more than are present now. There has to be a cost to hyper-reproduction to make this idea work, however. Otherwise, why not hyper-reproduce all the time? If an organism allots resources to its offspring which enhances its reproductive fitness, more offspring means fewer resources per individual. If resources are limited, it is an advantage to concentrate these resources on a few offspring.

I think Japan fits the bill. There is little need to genetically adapt to a stressful environment. The environment is presently supporting the maximum number of individuals, there is no pressure to fill a vacuum. There is an advantage to concentrating limited resources on a few offspring, which enhances their reproductive fitness.

I think these tendencies are instinctive, not so much a matter of choice.